Frankfurt public prosecutors said in a statement that the accused were seven current employees and one former employee of a "major bank," but did not identify the company involved.
Information obtained by AFP revealed it was Deutsche Bank, as reported earlier by the daily Süddeutsche Zeitung.
A Deutsche Bank spokesman declined to confirm the information. But the spokesman said that "the investigation into the carbon emission certificates is ongoing and covers all relevant facts. We are cooperating with the authorities concerned."
According to the prosecutors, the accused, aged between 33 and 64, participated in tax evasion on the certificates between September 2009 and February 2010.
The scheme is estimated to have cost Germany around €220 million in unpaid taxes via the purchase and sale of carbon emission certificates abroad.
Under a European Union trading system, limits are placed on the amount of carbon dioxide companies may emit, and those that pollute less are free to sell credits to companies that need more.
In December 2011, a Frankfurt court jailed three Britons, two Germans and a Frenchman for between ten months and seven years for their involvement in the scheme.
Deutsche Bank is mired in as many as 6,000 different litigation cases.